Production of 4-methylindan and 5-methylindan



: PRODUCTION OF 4-METHYLINDAN S-METHYLINDAN 3 Claims. (Cl. 260-668) Our invention relates to a method for theproduction of 4-methylindan' and S-methylindan' which have'the fol-' lowing structural formulas, respectively:

HaC Ha 4-methylindan and S-methylindan are useful chemical compounds in that by using conventional procedures, such as nickel-calcium phosphate catalysts, they can'bedehydrogenated to form 4-methylindene'and S-methylindene, respectively. Both 4-methylidene and S-methylindene can be polymerized alone 'or in admixture with eachother or with coumarone to form useful resinous products. A prior method for the production of the methyl indans involves dehydrocyclization of ethyl xylenes.

In accordance with our present invention, we have devised a new process for the production of 4-methylindan and S-methylindan which involves three essential steps, namely, the hydrogenation in liquid phase and with a conventional hydrogenation catalyst .of'a particular petroleum fraction, fractionating the hydrogenated prodnit d Sta es Patent O" uct to provide a particular cut, and then dehydrogenating that cut using a conventional dehyrogenation catalyst to yield a product which is "rich in 4-methylindan and 5- methylindan and from which those compounds can be separated in a high state of'puri'ty using conventional procedures.

The'petroleum fraction which is hydrogenated in the first step is one which boils withinthe range from 395-- F. to 410 F. The fraction is rich in 4-methylindan and S-methylindan, generally containing a total of from 15 to 40 percent by weight of those compounds, and moreover it is rich in prehnitene, generally containing from 10 to 20' percent by weight of that compound. The petroleum fraction boiling within the range from 395 F. to 410 F. can be obtained from any of a variety of sources, such as by fractionating a thermal or catalytic reformate manufactured with the aid of a platinum supported on alumina catalyst or a molybdenum oxide supported on alumina catalyst. Other sources of the petroleum fraction are fiuid gasoline, aromatic solvents, and so forth.

In the first step of our process, a petroleum fraction having the characteristics just described is selectively hydrogenated in the liquid phase while in admixture with a conventional hydrogenation catalyst, such as Raney nickel, nickel supported on alumina, platinum on alumina or palladium on alumina, nickel supported on cobalt, molybdenum oxide or sulfide, tungsten oxide or sulfide, and the like. As a general rule, the hydrogenation is carried out at a temperature within the range from 25 C. to 400 C., preferably from 25 C. to-250 C., and .at a hydrogen pressure varying from atmospheric to ice If desired, although not necessary, the hydrogenated product, before being fractionated, can be subjected to an operation whereby naphthenes are separated from aromatics. Methods for doing this are well known in the art, among them being the use of silica gel absorption, and the use of selective solvents such assulfur'dioxide, furfural; sulfuric acid and a mixture of diethyleneglycol and a small'amount of water (Udex).

After the petroleum fraction has been hydrogenated and, if desired, subjected to an operation for the removal of aromatics, the hydrogenated material is then fractionated in accordance with the conventional procedures to provide a'cut falling within the range from 355 F. to 370 F. This fraction is then dehyd'rogenated using a conventional dehydrogenation catalyst, whereby the 4- methylhexahydroindan is converted to 4-methylindan and S-methylhexahydroindan is converted to S-methylindan. Among thejdehydrogenationcatalysts which can be utilized "are platinum or palladium supported on alumina, chromium oxide supported on alumina, Standard Oil Development Company catalyst 1707 (72.4 MgO-- 18.4 Fe O 4.6 CuO-4.6 K 0), Shell 105 catalyst (90 Fe O 4 Cr O 6 K CO Ni-Ca phosphate, and the like. In carrying out the dehydrogenation, the operation is conducted in vapor phase, generally at a tempera- 3 ture within the range from 500 F. to 1500 F. and at a Example The petroleumfraction obtained by fractionating hydroformate to provide a cut boiling Within the range from 397 F.- to 400 F. was utilized as the starting material. This fraction had an n iof 1,5100, contained 96.6 percent by weight of aromatics and 3.4 percent by weight of olefins as determined by Florescence Indicator Absorbance, contained 15 percent by weight of prehnitene and 32 percent by weight of methylindans.

450 grams of the petroleum fraction was charged to a one liter bomb equipped with means for agitation, together with grams of Raney nickel catalyst which had been stored under water. Before use, the catalyst was washed four times with equal volumes of'ethanol for complete removal of the water from the catalyst. With agitation, the petroleum fraction was hydrogenated at 1200 p.s.i.g. (constant pressure) and at 300 F.-400 F. for approximately 3 /2 hours. Upon completion of the hydrogenation, the bomb wascoo'l'ed overnight under hydrogen pressure and the product was separated from the catalyst by decantation. The catalyst was not separated by filtration due to the. pyrophoric nature of the Raney nickel. To remove the last traces of catalyst and ethanol, the product was washed with water, filtered and dried over anhydrous potassiumcarbonate. By means of this procedure there was produced a product containing approximately 76 percent by weight of naphthenes, the remainder being essentially aromatics.

The hydrogenated fraction was then subjected to an operation for the removal of aromatics. This operation involved diluting the hydrogenated product with an equal volume of n-heptane and then passing the. mixture over silica gel, the weight ratio of silica gel to aromatics present being 20:1. By this procedure, aromatics were absorbed on the silica gel and there was provided a rafiinate of increased naphthene content.

The hydrogenation and the aromatic extraction procedures just described were repeated, but in this second case employing as a starting-material a 'hydroformate fraction boiling within the range frorn400 F. to 406 F. This fraction had a 11 of 1.5082, contained 96.7 percent by weight of aromatics and 3.3 percent by weight of olefins, contained 12 percent by weight ofprehnitene and contained 22 percent by weight of methylindans. In carrying out the hydrogenation, 474 grams of the petroleum fraction and 75 grams of Raney nickel catalyst were utilized, the pressure being 1100 p.s.i.g. As a result of the hydrogenation operation, the product contained approximately 75 percent by weight of naphthenes, the remainder being essentially aromatics.

The hydrogenated product was then treated with silica gel as was done with the other hydrogenated fraction;

The two raifiriates, were fractionally distilled to provide a narrow fraction boiling within the range; from 360 F. to 365 F. (11 greater than 1.4600). and a second fraction boiling within the range from 356 F. to 370 F. (71;; greater than 1.4530).

Both the narrow fraction and the broad fraction were dehydrogenated by passing them at 750 F. and 50 p.s.i.g. while in admixture with approm'mately 8.5 moles of hydrogen per mole of hydrocarbon into. contact with a catalyst consisting essentially of approximately 0.6 percent by weight of platinum supported on an alumina base at a weight hourly space velocity (weight units of hydrocarbon per weight units of catalyst per hour) of approximately 3. When this was done, there was'produced from the narrow fraction a product containing weight percent of 4-methylindan'and S-methylindan and from the broad fraction a product containing about 65 percent by weight of 4-methylindau and S-methylindan. A substantially pure mixture of 4-methylindan and- S-methylindan can be produced from either of the dehydrogenated products by simple fractionation, or preferably, by cracking of any ethyl trimethylbenzene, diethylmethylbenzene and isopropyldimethylbenzene present followed by fractionation of the cracked product. Alternatively, further purification can be performed following conversion to the methylindenes.

We claim:

1. A method for the production of a methylindan which comprises .hydrogenating in liquid phase and in admixture with a hydrogenation, catalyst a petrofeurn fraction boiling within the range from 395* F. to 410 F. containing a total 'of from 15 to 40 percent by weight or" 4-methylindan and S-methylindan and from 10 to 20 percent by weight of prehnitene to provide a hydrogenated product containing from 60 percent to percent by weight of naphthenes, fractionally distilling the hydrogenated product to provide a cut boiling within the range from 355 F. to 370 F and dehydrogenatingsaid cut in vapor phase in contact with a dehydrogenation catalyst to provide a product containing 4-methylindan and 5-methylindan.

2. The method of claim 1 wherein the hydrogenated product before being fractionally distilled is subjected to an operation whereby aromatic compounds are'removed.

3. The method of claim 1 wherein said hydrogenation catalyst is Raney nickel and wherein said dehydrogenation catalyst is platinum supported on alumina.

References Cited in the file of this patent UNITED STATES PATENTS Mattox- May 5, 1942 Holm Mar. 5, 1957 OTHER REFERENCES only) (Faraday II) Faraday: v01. 0 112 1954, (pages 10048.0().11 and 10049.001-1 only) (Faraday III). 

1. A METHOD FOR THE PRODUCTION OF A METHYLINDAN WHICH COMPRISES HYDROGENATING IN LIQUID PHASE AND IN ADMIXTURE WITH A HYDROGENATION CATALYST A PETROLEUM FRACTION BOILING WITHIN THE RANGE FROM 395*F. TO 410*F. CONTAINING A TOTAL OF FROM 15 TO 40 PERCENT BY WEIGHT OF 4-METHYLINDAN AND 5-METHYLINDAN AND FROM 10 TO 20 PERCENT BY WEIGHT OF PREHNITENE TO PROVIDE A HYDROGENATED PRODUCT CONTAINING FROM 60 PERCENT TO 85 PERCENT BY WEIGHT OF NAPHTHENES, FRACTIONALLY DISTILLING THE HYDROGENATED PRODUCT TO PROVIDE A CUT BOILING WITHIN THE RANGE FROM 355*F., AND DEHYDROGENATING SAID CUT IN VAPOR PHASE IN CONTACT WITH A DEHYDROGENATION CATALYST TO PROVIDE A PRODUCT CONTAINING 4-METHLINDAN AND 5-METHYLINDAN. 